Process of making picric acid.



GEORGE B. BRADSHAW, 0F ROSELLE PARK, NEW JERSEY.

PROCESS OF MAKING PICRIC ACID.

No Drawing.

To all whom it may concern:

Be it known that I, GEORGE E. BRADSHAW, a citizen of the United Statesof America, residing at Roselle Park, in the county of Union and Stateof New Jersey, have invented certain new and useful Improvements inProcesses of Making Picric Acid, of which the following is aspecification.

This invention relates to a process of making picric acid, and in itsmore intense aspect deals with the treatment ofpara-phenol-mono-sulfonic acid.

One of the objects of the present invention is to produce picric acid,preferably obtained by nitrating or otherwise treating certain phenolsulfonic acids.

Another object is to provide a simple and practical process for makingpicric acid which may be carried out in a shorter time and at lessexpense than processes heretofore proposed.

A further object is to provide a reliable, safe and eiiicient processfor manufacturing a higher grade of picric acid.

Other objects will be in part obvious and in part hereinafter pointedout.

The invention accordingly consists in the several steps and the relationand order of one or more of-those steps with relation to each of theothers thereof which will be exemplified in the hereinafter disclosedprocess and the scope of the application of which will be indicated inthe claims that follow.

While it may have been attempted to treat simultaneously certainphenolic bodies such as orthoand para phenol mono sulfonic acids for theproduction of picric acid, such processes have required a relativelylarge amount of time and expense, and it is believed that theseobjections, among others, mav be fully overcome by nitrating thephenolic bodv, when all of the phenol is in the form ofpara-phenol-mono-sulfonic acid.

The process may be carried out in its mechanical aspect-in numerous waysknown to those familiar with the subject and the following may be c tedas apreferable exam le: One part of phenol is first sulfonated withabout 15% more sulfuric acid of about 93% streng h than theoreticallyrequired to form phenol-sulfonic acid and the resulting mixture oforthoand para-mono-sulfonic acids is ,all substantiallv changed to para--mono-sulfonic acid by diluting with water till the mixture is about 30Be, and then boiling with live steam thoroughly. A hun- Specification ofLetters Patent.

Patented Jan. til, ll-916$.

Application filed November 8, 1915. Serial No. 60,279.

dred gallon batch may be boiled three hours. The resulting dilutesolution of para-phenolmono-sulfonic acid of about 20 B, is thengradually added to three and one-half parts of nitric acid of about 40 Bduring which the temperature should be kept relatively low. After thereaction subsides the mixture is heated to a temperature of about 200 F.until the reaction has completely occurred. The mass is then allowed tosettle and cool, and the picric acid crystallizes out and is removed inthe usual way.

A second method is to change the ortho sulfonic into para sulfonic byheating to 260 F. with excess sulfuric acid While stirring. Thisprocedure would be used where metal nitrating vessels are employed andall dilution of acid must be avoided.

It is thus seen that this invention produces a desirable, simple,practical and inexpensive process of making picric acid and is believedto accomplish, among others, all of the objects, and advantages hereinset forth.

As many changes could be made in carrying out the above process withoutdeparting from the scope of the invention, it is contended that allmatter contained in the above description shall be regarded asillustrative and not in a limiting sense.

I claim as myinvention:

1. The herein described process of producing picric acid comprising thesteps of converting phenol completely into para-phenol sulfonic acid andnitrating said para-phenol sulfonic acid.

2. The herein described process of producing picric acid comprising thestep of nitrating substantially pure para phenolmono-sulfonic acid.

3. The herein described process of producing picric acid comprising thestep of ni; trating substantially pure para phenolmono-sulfonic acid andcompleting the nitration by the application of heat.

4. The herein described process of producing picric acid comprising thesteps of converting phenol into substantially pure para phenol sulfonicacid in the presence of water so as to form a dilute solution thereof,mixing three and one-half parts of nitric ac d of about 40 B with one pat of said solution, heating the mix ure until the reaction is completed,and-f.all0wing the picric acid to crvstallize out of the reacti e mass.

5. The herein described proc ss o oducing picric acid which consists insulfonating phenol 'to produce a mixture of phenolafter which the picricacid is allowed to mono-sulfonic acids, diluting the mixedsulcrystallize. l0 fonic acids w th Water and boiling the Same Intestimony whereof I alfix my signature with steamto convert the sameinto aqueous in the presence of two Witnesses.

solution of substantially pure para-mono- GEORGE B. BRADSHAW. sulfonicacid, mixing the said solution with Witnesses: nitric acid and thenfinally heating the same CLARENCE CHURCHILL,

to ,a temperature of approximately 200 F. JAMES HARPER.

